Very interesting data suggests that patients randomized to bupropion SR (Wellbutrin) lose more weight and keep it off than patients taking placebo. Report: Anti-depressant helps keep weight off, too

"There are no magic bullets for treating obesity. Diet and exercise are still the keys to long-term weight loss. But this does give us another arrow in the quiver in helping to treat it."

The study, reported in July's Obesity Research, was paid for by the drug's manufacturer, GlaxoSmithKline.

During the first half of the 48-week study, 227 obese people were randomly assigned to take one of two doses of bupropion or a dummy pill each day. Participants also were on a restricted diet and asked to increase their exercise by about 50%.

Those on the higher dose of bupropion lost 10% of their body weight compared with 7% for those on the lower dosage. Those who took the dummy pill lost about 5% of their body weight.

In the second 24 weeks, 192 participants who completed the first part of the study were all given bupropion and were able to sustain their weight loss.

Those on the higher dose maintained an 8.6% loss and those on the lower dose maintained a 7.5% loss.